The patent application referenced above is incorporated herein by reference, particularly FIGS. 11, 12A-12F, 16, 17, 26, and 31-34 and the descriptions related thereto on pages 21-24, 26, 32-33, and 37-41 in the specification. This application describes, inter alia, the use of physical control devices that may be applied to a resistive-type touch screen to emulate mechanical control devices such as knobs, faders, joysticks, and mouse devices, provoking touch detections that are interpreted by software as control movements of the control devices. These touch detections are generally located within a screen area adjacent to the control device base, which is adhered to the outer surface of the touch screen.
It has been observed that the locus of the touch detections provoked by a physical control device is not confined within the outline of the base of the control device. When a control device such as a post is operated on the surface of a resistive touch screen, it presses on singular points of the touch screen, those points extending along the perimeter of the base of the post The locus of these touch points is generally a closed curved shape that is roughly centered with respect to the base of the post. It has been observed, however, that a certain amount of these touch detections are located outside the perimeter of the base, and may be spaced therefrom at a not insignificant distance. Thus a control device such as a post may generate touch detections at some distance from its location on the screen.
This distant touch phenomenon may be problematic when the control device is combined with on-screen active devices such as switches or other touch sensitive control areas that are actuated by a finger touch, stylus touch, or the like. For example, as shown in FIG. 1, a knob controller 11 comprised of a post may be joined to a resistive touch screen 12 to provoke touch inputs to the screen 12, and these touch inputs may be recognized as knob rotation, joystick directional movements, or mouse movements. In any case, fingertip operation of the controller 11 involves pressure applied through the perimeter of the base of the post that tends to generate closed curved loci 13 of touch detection points. Note that some of these closed curved loci 13 are spaced outwardly from the controller 11.
Generally the controller 11 is employed in combination with one or more virtual displayed devices portrayed on the display that is associated with the touch screen 12. Each virtual displayed device corresponds to a respective area on the touch screen, and any touch within that area is interpreted as a command to actuate the virtual displayed device. For example, a switch 14 may be placed proximate to the controller 11, and the switch may or may not have a function that interacts with the controller 11. However, it is clear from the fact that one or more locus of possible touch points of the controller 11 extends to intersect the touch sensitive area of the switch 14. Thus it is possible for a touch detection of knob controller 11 to generate a false touch command at the switch 14.
This potential problem could be solved by software that turns on and off the touch detection associated with physical control devices such as controller 11 and selectively ignore touch detections within some default distance of the physical controller. This solution would require a user to switch constantly between two modes: physical control devices enabled and virtual displayed devices disabled, and vice versa. This requirement is not consonant with an underlying concept of the invention, which seeks to provide seamless interaction between the devices displayed virtual displayed devices and the physical devices adhered to the touch screen.